The son of an imprisoned Belarusian opposition leader says his father has suffered a stroke, probably because prison officials refused to give him his needed medication.

Pavel Marinich accuses officials of essentially trying to kill his father, Mikhail, who was jailed in December on charges of theft of property from the U.S. Embassy in Minsk.

U.S. officials had said they had no claims against the elder Mr. Marinich, who was a former economics minister and ambassador. He suffered a stroke last week.

A prominent United States senator, Republican John McCain, has accused Belarusian authorities of committing what he calls very serious human rights abuses by allegedly blocking access to Mr. Marinich and denying him proper medical care.

Critics accuse the government of President Alexander Lukashenko of stifling media freedom, political dissent and democracy.